Read a full match report of the FA Cup third-round game between Southampton
and Chelsea at St Mary's Stadium on Saturday Jan 5, 2013.

It required a mere 35 minutes for Demba Ba to make his imperious statement in Chelsea’s royal blue, as the Senegalese striker marked an extraordinary debut for the club with two beautifully-taken goals. No wonder Fernando Torres, exiled to the bench for this savage dismembering of a toothless Southampton, watched on with such a thunderous expression.

To emphasise the contrast, Torres had needed 12 hours and 20 minutes to register his first strike in his 14th game for Chelsea. And lest we forget, he cost Roman Abramovich £43 million more than that unerring poacher Ba.

Finally, if belatedly, the owner can feel as if he is deriving some semblance of value for money from his front men.

Ba’s brace also helped safeguard Chelsea’s superlative recent FA Cup record, encompassing four triumphs in the past decade. Few would discount a fifth on the evidence of this wholly convincing win, which featured another goal for Frank Lampard, who drew level with Kerry Dixon as the club’s second all-time leading scorer on 193.

Perhaps the only negative for Chelsea was the conduct of the fans, who detonated a firecracker in the crowd and threw a flare on to the pitch after Ba’s second. They also continued to round on interim manager Rafael Benítez with familiar chants of “fat Spanish waiter”. The Spaniard, despite inspiring this polished performance 72 hours after the league defeat to QPR, seems to be facing a losing battle to establish any degree of popularity.

For his own sanity, he chose to concentrate on Ba’s display. “He was really good,” Benítez said. “It’s always important for a striker to score goals but more than that it is the contribution to the team and the understanding of what we want to do.”

Ba was supported by a consummate exhibition of midfield creativity from Juan Mata, who was central to Chelsea’s every attack. But it was Southampton who struck first, as Jason Puncheon slid a perfect pass into the path of Jay Rodriguez, who who turned a low finish beyond Ross Turnbull.

Chelsea summoned a sense of urgency, with Eden Hazard curling an elegant strike within inches of Artur Boruc’s far post. This first spell of any pressure created the perfect opportunity for the debutant to flourish.

Juan Mata, inventive as ever, contrived to scoop the ball over the onrushing Boruc, and immediately Ba sensed blood. Scampering to the line to make sure he applied the final touch, he stuck out a leg and a first goal in Chelsea colours was his.

Chelsea were beginning to win the battles in midfield, courtesy of Mata and Hazard’s clever running. Cue Victor Moses to gatecrash the party with almost the final kick of the first half, demonstrating immaculate technique to seize upon Ashley Cole’s lay-off and lash a half-volley past Boruc. “It was the wrong time for us to concede,” lamented Southampton manager Nigel Adkins.

So it proved. Why, not even Branislav Ivanovic, rather less cultured in front of goal than the stylish Moses, would be denied as Chelsea continued their onslaught. He could thank Mata for the assist, after the Spaniard lofted an exquisite pass for him to dispatch an emphatic header.

There was time for Ba’s afternoon to become more memorable still. Meeting a neat pass from Hazard out on the right, he proved his instincts as a striker are as sharp as ever in heading his second goal for Chelsea, and his 15th of the season overall. The only man in blue apparently not celebrating was Torres, whose expression on the bench was bleak and pensive.

The final flourish of a decisive victory was supplied, aptly, by Lampard. Left-back Maya Yoshida was adjudged to have handled in the box and up stepped the substitute midfielder and perennial Chelsea favourite to stroke home the penalty to equal Dixon’s total.

“It is a great achievement for Frank,” said Benítez, who again refused to shed any light on Lampard’s continued contract negotiations. “I know they have conversations sometimes but the main thing for me as a coach is to bring the best out of him.”

And yet the fans’ pressure cannot be escaped. By the final whistle, the cries from the away end of “sign him up” had grown louder than ever.nalty to equal Dixon's benchmark. The cries from the away end of "sign him up" grew louder than ever.